That is actually the expected behavior.
The HTTP Security property sets the minimum required. So when set to None it will accept both http and https.

If you are viewing the documentation using https that means your server has https configured, so the url shows https. If you access the documentation using http it will show a http url unless the property is set to SSL/TLS.
It is also by design that there is no way to set a service to be only available in http, since https should always be prefered if the server has it configured.

Thanks for your reply.
We have a setup like in which all external comm's are HTTPS using Tibco ESB and all internal comm's don't per sé need HTTPS (since it has some ms in response overhead but that's no real argument).

For now I'm just testing anyway but the HTTPS url will definately not work for some reason.

Anyway; this somehow feels like:
I've explicitly asked for a front door without a lock.
The supplier gave me a door with a lock anyway but didn't lock it.
In the description of how to open however it says: "You always need to unlock your door first."